Do Potatoes Cause Diabetes?

By May 16 2012

and/or . In addition, most all baked potatoes are served with , sour cream and/or cheese.

Are potatoes dangerous? Do potatoes cause diabetes? The following analysis represents these important differences. They are of a serving of mashed potatoes, a You might think so if you followed the headlines. In loaded baked and a plain baked potato as served 2006, the media was full of reports making these claims, in a popular national restaurant chain. They are typical some of which are still being made today. All of this for how mashed potatoes and baked potatoes are often attention was based on the results of a study published in served and consumed in America. In addition, I have 1 the American Journal of Clinical . included the analysis of a plain medium baked potato for comparison. The prospective study followed 84,555 women in the famed Nurses’ Health Study. At the start, the women, Mashed Potatoes (Restaurant): aged 34–59 years, had no history of chronic disease, and completed a validated food frequency questionnaire. 367 calories These women were then followed for 20 years with 24 grams of repeated assessments of their . The study 59% calories from fat concluded, "Our findings suggest a modest positive 11.4 grams of association between the consumption of potatoes and the 28% calories from saturated fat risk of in women. This association was 9 milligrams of cholesterol more pronounced when potatoes were substituted for whole grains.” Loaded Baked Potato (Restaurant):

So, let’s take a closer look at the study and see how 505 calories accurate these claims are, and where the truth really lies. 22 grams of fat Specifically, we will look at five key points. 39% calories from fat 10 grams of fat Are all potatoes equal? Or “When is a potato not a 18% calories from saturated fat potato?” 30 milligrams of cholesterol

In the study, participants were asked how often, on Regular Baked Potato (Restaurant): average, in the previous year, they had consumed potatoes. The options they were given to choose from 329 calories were either: 4.5 grams of fat 12% calories from fat a) One baked or one cup mashed potato .4 grams of saturated fat b) 4 ounces of french-fried potatoes 1% calories from saturated fat 22 milligrams of cholesterol These were the only two choices the subjects could pick from. So, while these may represent how potatoes are Baked Potato (Home): often consumed here in America, they do not account for any differences in how the potatoes were prepared 160 calories and served. And mashed potatoes were counted in with .2 grams of fat baked potatoes, which are two completely different 1% calories from fat forms of preparing potatoes. .1 grams of fat .05% calories from saturated fat In America, whether it is at home or in restaurants, most 0 milligrams of cholesterol all mashed potatoes are made with milk and butter

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By May 16 2012

So, compared to an at-home, plain baked potato: effects of the overall Western dietary pattern.”

The mashed potato gets more than ½ its calories, The researchers found that the study subjects who ate plus nearly all its fat (about 24 grams) and more potatoes also ate more , more refined cholesterol (9 mgs) from "non-potato" grains and consumed more total calories (in fact more ingredients; than 500 additional calories per day). In addition, potato The loaded potato gets more than 2/3 of its intake was also associated with higher intakes of calories, plus nearly all of its fat (about 22 saturated and trans fat, and less physical activity. grams) from "non-potato" ingredients; Even the regular baked potato from the So, was the potato the problem, or was the potato a restaurant gets ½ its calories, plus nearly all its marker for a dietary pattern and lifestyle that was fat (about 4 grams) and cholesterol from "non- responsible for the results? In this study, the potato potato" ingredients (most likely oil and/or butter seems to be a marker for a high-fat, high refined grain used on the outside and/or as a regular topping). diet.

As we can see, the potato is contributing only a small Trends and Truth in Taters percentage to what is most likely being counted as “potatoes” in this study. The association applied to If a food really is a causative factor in a disease, then as potatoes may be more accurately applied to how we consume more of the food (as an individual or as a potatoes are prepared and consumed and the toppings nation) we should see the disease rates go up they are served with here in America, more so than just accordingly. In addition, when we remove or lessen the the potato itself. The study admitted that "cooking consumption of the food, we should see disease rates (as methods" were not assessed, so it is safe to assume that an individual or as a nation) go down. However, this is these were typical Americans consuming potatoes in the not the case for potatoes and diabetes. Let’s take a closer way they are typically served. look:

In addition, other studies on the Nurses database show Total Potato Consumption per person per year: the majority of their diets are not low fat, low saturated fat, low cholesterol or high fiber which confirms that 1970: 122 pounds they are not choosing or consuming the healthier 1996: 145 pounds versions. 2008: 117 pounds

So, when is a potato not a potato? When nurses in Prevalence of Diabetes (% of population): America consume them.

The Potato: Is It a Marker for Something Else? 1970: 2.00% 1996: 2.89% In this study, was the potato the problem itself, or was 2008: 6.29% the potato acting as a marker and pointing to something else that was associated with potato consumption? We see here that consumption of potatoes is trending down since 1996 yet the prevalence of diabetes is rising Quoting the researchers: faster than ever. In fact from 1996 to 2008, potato consumption fell 19% while the percentage of people "White potatoes and are large components of with diabetes increased by more than 200%. a “Western pattern” diet. This dietary pattern is characterized by a high consumption of red meat, refined Most importantly, the prevalence of diabetes really grains, processed meat, high-fat dairy products, desserts, began to increase in 1996-1998, which is the same time high- drinks, and eggs, as well as French fries and that potato consumption began to fall sharply. potatoes. A Western pattern diet previously predicted a risk of type 2 diabetes. Thus, we cannot completely Replication separate the effects of potatoes and French fries from the

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By May 16 2012

In science, the results of any one study are always 1 Potato and French fry consumption and risk of type 2 diabetes in interesting but never prove anything unless they can be women– Am J Clin Nutr 2006;83:284 –90. replicated and/or reproduced. Reproduction and 2 replication are what increase the validity of any claim. “Dietary Patterns and Risk for Type 2 Diabetes Mellitus in U.S. Men. Ann Intern Med. 2002;136:201-209. In a 4-year prospective study of 36,787 adults which was 3 Dietary Patterns and Diabetes Incidence in the Melbourne done one year later, researchers investigated the Collaborative Cohort Study Am J Epidemiol 2007;165:603–610 association between a variety of dietary patterns and type 2 diabetes.3 The study results, which were published in the American Journal of Epidemiology, found an association between potatoes and diabetes only when they were cooked with oil. In fact, they concluded that consuming a variety of cooked , including potatoes, cooked in ways other than , was associated with a reduced risk of developing type 2 diabetes.

Other studies, similarly, have not found any correlation between diabetes and plain potatoes, and another also showed a decrease incidence of diabetes.2,3

What Causes Diabetes and Do Potatoes Play a Role?

During the 20 years that the subjects in the Nurses study were followed, we saw a dramatic shift in the dietary and lifestyle pattern of Americans. Not only has potato consumption and the type of potato changed dramatically, but there have been significant changes in other areas. Americans have sharply increased their consumption of refined /sweeteners, /, added oils/, hydrogenated fats/trans fat, cheese, calories, etc. Meanwhile the percentage of Americans who are overweight, and even obese, increased, while the percentage who are active fell dramatically.

These factors, and not the potato itself, are what is responsible for the dramatic increase in the incidence of diabetes. Sure, mashed potatoes, loaded baked potatoes and french-fries, which are calorie dense, high in fat, saturated fat, cholesterol, sugar, and increase your risk for disease and should be avoided.

However, there is no credible evidence that potatoes, when consumed close to their natural state and cooked conservatively by baking, boiling, and/or steaming, will cause diabetes or are associated with an increased risk. In fact, potatoes have long been part of healthy diets around the world.

A more detailed version of the article was published here.

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